Keisha writes that if an object has any external forces acting on it, then the object can be in dynamic equilibrium but not static equilibrium. Which statement best describes Keisha’s error? An object that is not moving is always in static equilibrium. An object that is moving must be in dynamic equilibrium. An object in either state of equilibrium must have no forces acting on it. An object in either state of equilibrium must have no net force acting on it.

Consider the linear model for a two-stage nested design with b nested in a as given below. yijk=\small \mu + \small \taui + \small \betaj(i) + \small \varepsilon(ij)k , for i=1,; j= ; k=1, assumption: \small \varepsilon(ij)k ~ iid n (0, \small \sigma2) ; \small \taui ~ iid n(0, \small \sigmat2 ); \tiny \sum_{j=1}^{b} \small \betaj(i) =0; \small \varepsilon(ij)k and \small \taui are independent. using only the given information, derive the least square estimator of \small \betaj(i) using the appropriate constraints (sum to zero constraints) and derive e(msb(a) ).